Fall protection device for a hoist

Abstract

A hoist, a hoisting apparatus with said hoist and a method for securing a hoist. A hoist body having a drive mechanism for raising or lowering a hoist chain or a hoist cable is suspended from a support device by a hoist support. A safety device having a loosely arranged coupling element and a damping element is mounted between the hoist body and the support device. If the hoist support is released, the hoist body can drop by a drop height until the coupling element becomes taut. The damping element then damps the fall under the load of the hoist body, the hoist chain and whatever load is suspended from it.

Claims

1. A hoist comprising a hoist suspension means for suspending a hoist body from a support device, wherein a drive for raising or lowering a hoist chain or hoist cable is provided on the hoist body, wherein a safety device, comprising a damping element and a loosely movable coupling element attached thereto, is provided between the hoist body and the support device.

2. The hoist according to claim 1, wherein the damping element comprises at least one deformable deforming portion.

3. The hoist according to claim 2, wherein the damping element comprises two coupling portions arranged at a distance from one another for coupling to the coupling element at one side and to the hoist body or to the support device at the other side, and wherein the deforming portion is arranged between the coupling portions.

4. The hoist according to claim 3, wherein the damping element is shaped such that at least one part of the damping portion thereof extends at an angle of more than 45 relative to an imaginary line that extends between the coupling portions.

5. The hoist according to claim 3, wherein the deforming portion comprises at least two leg portions that are at an angle of 90 or less to one another.

6. The hoist according to claim 2, wherein the drive is designed to lift a maximum load, and the deforming region is designed such that the deforming element lengthens by at least 10% at half of the maximum load.

7. The hoisting device according to claim 6, wherein the coupling element has such a length that the coupling element becomes taut after a drop height of 20 to 200 mm.

8. The hoist according to claim 2, wherein the damping element comprises at least one deflection in the deforming portion, such that the damping element has a shape that is deflected in a transverse direction.

9. The hoist according to claim 2, wherein the damping element in the deforming portion comprises at least one first deflection, wherein the damping element extends so as to be deflected in a first transverse direction, and the damping element comprises a second deflection, in which the damping element extends so as to be deflected in a second, opposite transverse direction.

10. The hoist according to claim 2, wherein the damping element comprises at least one part that extends integrally between an upper and lower coupling portion.

11. The hoist according to claim 2, wherein the damping element is designed as a flat, curved part.

12. The hoist according to claim 11, wherein at least one bead is provided on the deforming portion.

13. The hoist according to claim 1, wherein the coupling element is designed as a chain, cable or other strand-shaped element.

14. A hoisting device, comprising a support device and a hoist according to claim 1, wherein the hoist body is suspended from the support device by the hoist suspension means, and the coupling element has such a length that it is arranged loosely.

15. The hoisting device according to claim 14, wherein the coupling element has such a length that a rotation of the hoist body by more than 20 about a vertical axis of rotation is made possible by the hoist suspension means.

16. A method for securing a hoist, wherein a hoist body comprising a drive for raising or lowering a hoist chain or hoist cable is suspended from a support device by a hoist suspension means, and a safety device comprising a loosely arranged coupling element and a damping element is attached between the hoist body and the support device, wherein, when the hoist suspension means is released, the hoist body falls by a drop height until the coupling element becomes taut, and after the coupling element becomes taut, the damping element damps the fall of the hoist body.

Description

(1) In the following, an embodiment of the invention is described in more detail on the basis of drawings, in which:

(2) FIG. 1 shows a side view of a first embodiment of a hoisting device comprising a hoist;

(3) FIG. 2 shows a perspective view of the hoist from FIG. 1;

(4) FIG. 3 shows a rear view of the hoist from FIG. 1, FIG. 2;

(5) FIG. 4, 5 show a rear and a perspective view of a first embodiment of a damping element on the hoist from FIGS. 1 to 3;

(6) FIG. 6 shows a side view of a second embodiment of a hoisting device comprising a hoist;

(7) FIG. 7 shows a perspective view of the hoist from FIG. 6;

(8) FIG. 8 shows a rear view of the hoist from FIG. 6, FIG. 7;

(9) FIG. 9, 10 show a rear and a perspective view of a second embodiment of a damping element on the hoist from FIGS. 6 to 8;

(10) FIG. 11a-11e show schematic representations of further embodiments of damping elements.

(11) FIG. 1 shows a first embodiment of a hoisting device 10 for a load 12, which is shown here in a merely symbolic manner. A hoist 16 is suspended from a support device 14, e.g., a beam, a crane trolley, a crane, or the like, also shown merely symbolically here. The hoist 16 comprises a hoist body 20, for example a housing, in which a drive (not shown here in greater detail) for a hoist chain 18 is arranged, such that, by means of a motor arranged in the hoist housing 20, e.g., a pneumatic, electric or hydraulic motor, the hoist chain 18 can either be drawn in to raise the load 12 or released to lower the load 12.

(12) The hoist 16 comprises a suspension hook 22 having a hook lock for suspension from a part of the support device 14, shown merely schematically here. The attachment of the hoist 16 to the support device 14 enables a certain degree of movability of the hoist 20, inter alia, a rotation thereof. The suspension hook 22 comprises a revolute joint (not shown) in the example shown, such that it is attached to the hoist housing 20 so as to be able to rotate about a vertical axis. However, in alternative embodiments, the suspension hook 22 may also be rigidly attached to the hoist housing 20. In this case, too, a certain degree of movability is afforded to the suspension hook 22 on the support device 14.

(13) In addition, a safety device 24 is provided between the hoist housing 20 and the support device 14. In the example shown, this safety device comprises a safety chain 26 and a damping element, which is designed as a deforming bracket 28 in the preferred embodiment shown.

(14) In the first embodiment, the deforming bracket 28 comprises a lower coupling portion 30, to which said deforming bracket is rigidly connected to the hoist housing 20 using screws 32. The deforming bracket 28 further comprises an upper coupling portion 34 in the form of a lug, to which the safety chain 26 is attached. A deforming portion 36 is formed between the upper coupling portion 34 and the lower coupling portion 30 of the deforming bracket 28. The shape of the deforming bracket 28 is in particular visible in FIG. 4, 5 and is described in more detail below.

(15) As shown, the safety chain 26 is fastened by one end to the upper coupling portion 34 of the deforming bracket 28 and by the other end (shown merely symbolically) to an element of the support device 14. In this case, the safety chain 26 is longer than the distance between the upper coupling portion 34 of the deforming bracket 28 and the attachment point to the support device 14, such that the safety chain 26 is attached loosely between the two points and is force-free. The entire load is received by the suspension hook 22 in normal operation.

(16) The length of the safety chain 26 is such that a rotation of the hoist housing 20 relative to the support device 14 is possible up to an angle of rotation of approx. 180.

(17) As shown, the safety device 26 is arranged at a short horizontal distance, preferably of a few centimeters, from the hoist suspension means 22. The safety device therefore constitutes an entirely separate second suspension means, albeit not initially under load, in the embodiment shown.

(18) The hoist 16 and the safety device 24, and in particular the arrangement of the deforming bracket 28 thereon, can be seen in greater detail in the perspective view of FIG. 2 and rear view in FIG. 3. In these cases, the load 12 and the support device 14 have not been shown again.

(19) In the embodiment shown in FIG. 2, FIG. 3, and also in FIG. 4, 5, the deforming bracket 28 is composed of two symmetrical parts which are each formed as bent, flat elements. The lower coupling portion 30 adjoins the housing of the hoist body 20 and partially surrounds same. The deforming portion 36 and the upper coupling portion 34 are integrally formed with the lower coupling portion 30 from a strip-shaped element having a width of approx. 40 mm. The deforming bracket 28 is manufactured from a flat steel material having a thickness of, for example, 5 mm in the example shown. In alternative embodiments, the width and thickness may be selected differently, the thickness values preferably lying within a range of 4 to 8 mm.

(20) As can in particular be seen in FIG. 4, the central deforming portion 36 of the deforming bracket 28 comprises a deflection in the horizontal direction, i.e., transversely to an imaginary line that connects the upper coupling portion 34 to the lower coupling portion 30.

(21) In the deforming portion 36, the deforming bracket 28 comprises an upper, substantially horizontally oriented leg 38 on each of the two sides thereof, which leg extends outward from the upper coupling portion 34, and subsequently, over a bend 42, a second leg 40, which extends from the outside inward.

(22) The deforming portion 36 therefore comprises curves 42, such that the legs 38 are each at an angle 1, 2 of more than 45 to an imaginary line (shown as a dashed line in FIG. 4), which extends between the coupling portions 34, 30 (more precisely, between the fastening points there).

(23) Both legs 38, 40 are at an acute angle to one another, which angle is slightly over 20 in the example shown. In total, three curves 42 are therefore formed on the deforming bracket 28 in the example shown.

(24) As already explained, the safety chain 26 can move loosely in normal operation of the hoisting device 10. In the event of failure of the hoist suspension means 22, a certain drop height of the hoist body 20 together with the hoist chain 18 and suspended load 12 is therefore produced, until the safety chain 26 becomes taut. Then, strong tensile loading is produced between the coupling portions 30, 34 of the deforming bracket 28.

(25) On account of the deflected shape, i.e., in the example shown, the horizontal course of the legs 38, 40, i.e., transversely to the substantially vertical tensile loading, the deforming bracket 28 will deform under the sudden tensile loading that occurs after the safety chain 26 becomes taut. In the process, the angle between the legs 38, 40 widens. The deforming portion 36 thus lengthens, a plastic deformation in particular taking place at the bend points 42.

(26) On account of the deformation upon simultaneous elongation, the fall of the hoist body 20 and the load 12 is caught over a certain braking distance. Although abrupt loading occurs again in both the safety chain 26 and the hoist chain 18 after full elongation of the deforming bracket 28, this loading however is significantly reduced in comparison to a rigid, non-deformable attachment of a safety chain 26.

(27) In one embodiment, the length of the safety chain 26 may for example be dimensioned such that the safety chain 26 becomes taut after a drop height of 60 mm. A load of, for example, one ton would lead to a peak load of approx. 7 t without the deforming bracket 28, which could lead to failure of the hoist chain 18, for example.

(28) On account of a deformation of the deforming bracket 28, which results in an elongation of approx. 60 mm, the peak load can be reduced to approx. 5 t, for example, in otherwise identical conditions. Depending on the geometry and thickness of the deforming bracket 28, other values may also be achieved. As such, by means of an appropriate design, failure of the hoist chain 18 or of other components of the hoisting device 10 or support device 14 can be prevented.

(29) In FIGS. 6 to 10, a second embodiment of a hoisting device comprising a second embodiment of a damping element is shown. In this case, the second embodiment corresponds in many respects to the first embodiment. Identical parts are provided with the same reference numerals. In the following, only the differences regarding the second embodiment with respect to the first embodiment are described. Apart from that the description given above applies to both embodiments.

(30) In the case of the second embodiment, a safety cable 26a instead of a safety chain is provided as a component of safety device 24. The safety cable 26a is attached to a deforming bracket 28a that differs from the deforming bracket 28 according to the first embodiment as described in greater detail below.

(31) The lower part of the safety cable 26a is attached to the upper coupling portion 34 of the deforming bracket 28a. The upper part of said safety cable forms a cable loop that is placed loosely around the support device 14, i.e., around a beam, in the example shown. The safety cable 26a is in this case longer than is required for attachment thereof, such that a rotation of the hoist housing 20 relative to the support device 14 is possible to the same extent as in the safety chain 26, i.e., up to an angle of rotation of 180.

(32) The deforming bracket 28a has the same shape as the deforming bracket 28 according to the first embodiment, i.e., it comprises two symmetrical, curved flat elements having a central deforming portion 36. The deforming bracket 28a is also composed of a flat material, preferably steel, however beads 35 are additionally provided on the curves.

(33) In the embodiment shown, the beads 35 are each designed as recesses in the direction of the outer face of the relevant curves.

(34) On account of the beads 35, a higher flexural resistance is produced on the curves of the deforming bracket 28a. In the event of a fall, a larger amount of deformation energy can therefore be absorbed in comparison to a curved flat material of the same strength.

(35) While the elements shown are the currently preferred embodiments of the invention, these elements should be understood merely as exemplary and non-limiting. In fact, the invention can be realized by means of a variety of embodiments.

(36) For example, instead of the symmetrical deforming brackets 28, 28a shown, an asymmetrical deforming element may be used, as shown by way of example in FIG. 11d.

(37) Indeed, the shape of the deforming element may differ significantly. Instead of the depicted shape comprising straight portions 38, 40 and rounded curves 42, purely curved shapes may also be used, for example, as shown by way of example in FIG. 11b. Instead of the depicted shape comprising a single deflection in the transverse direction, a plurality of successive deflections may be provided along the course of the deforming portion 36, i.e., a larger number of legs may be provided, for example. Instead of the depicted angles of the individual curves 42, other values may also be selected, such that the legs 38, 40 can be arranged differently relative to one another, as shown by way of example in FIG. 11a.

(38) The load acting on the deforming portion 36 of a deforming element 28 is a tensile load in preferred embodiments. However, as the alternative embodiment according to FIG. 11c shows, compressive loads may also be produced.

(39) In all embodiments of deforming portions, beads may be provided on the curves in order to achieve greater flexural rigidity.

(40) Finally, a damping element may be designed having a friction element instead of a deforming element, as shown by way of example in FIG. 11e. Coupling portions 34, 30 are in this example connected to a cylinder 46 and a piston 48. A fluid 50 is arranged in the cylinder 46 and the piston 48 can move inside the cylinder 46 in such a way that, during loading, the fluid is pressed through an annular opening 52 left around the cylinder 48.

(41) Therefore, the damping element shown by way of example in FIG. 11e can also damp the falling movement over a braking distance when the load acts on the coupling portions 34, 30.